Rating Windows for Condensation Resistance

This time of year we get a lot of questions about condensation (or frost) problems. Rest assured, your windows are not the cause of condensation. Other external factors can be causing your windows to have condensation. It is important to determine where the condensation is forming on the window. This will lead you to causes and solutions.

Window Rating Tools:

There are two competing standards that are used to measure a windows condensation resistance. One is the Condensation Resistance Rating (CR) and the Condensation Resistance Factor (CRF).

While both of these ratings cannot guarantee you window will resist condensation they can give you an idea as to how well your window can resist condensation under certain conditions. A window’s condensation resistance is primarily focused on improving and maintaining proper humidity levels in the home. High humidity levels in the home will increase the likelihood of window condensation.

Humidity Reduction Tips

1. Make sure all sources of ventilation to the outside are functional and use kitchen, bathroom and laundry room exhaust fans during and after humidity-producing activities to vent excess moisture.
2. Air out your home periodically. Opening windows for just a few minutes a day lets the stale moist air escape and the fresh dry air enter without compromising your heating.
3. Check your humidifier settings. Use the humidity comfort levels provided in the table to correctly set and balance the humidity level in your home.
4. Be sure that all louvers in the attic or basement are open and large enough. You can even open your fireplace dampers to allow excess moisture to escape.
5. If you have a large amount of house plants, try to concentrate them in one area and be careful not to over water.
6. If troublesome condensation persists, see your heating contractor about an outside air intake for your furnace, venting of gas burning heaters and appliances, or installation of ventilating fan

Condensation on the inside or outside of the window:

Moisture that appears in cold weather on interior of the glass can be an annoying problem. However, rest assured that windows are NOT the cause of condensation. Interior condensation is due to excess humidity in your home. Exterior condensation is a form of dew.

• Condensation happens when warm moist air comes into contact with cooler surfaces as the outside temperature drops
• Condensation means there is excessive indoor humidity – which can be doing damage to other parts of your home.
• High energy efficiency windows reduce air leakage – therefore, moisture created by bathrooms, kitchens, laundries, plants and occupants can result in a higher relative humidity.
• Windows usually experience more condensation where inside air circulation around windows is more restricted.

Condensation in between the glass:

Condensation in between the panes of glass in a double- or triple-glazed window is the result of a seal failure.

If you are a customer, New York Sash windows warranties that insulating glass units will not fail. Should you experience a seal failure, please submit a service request and we will work to resolve this issue for you as quickly as possible.

Otherwise, we’d be happy to meet with you to do an inspection of your window and offer replacement solutions and options.